main bearings

[Mouglie]

There are two options for the Main bearings on the 1.6, there
is .10" (.50mm) o/s and there is std.

I'm assuming std stands for standard and not what we learned
in health class

I'm confused as to which one i should get.

[channelmaniac]

You should take a micrometer and measure things... and try some plastigauge...

[MadMerv]

You only want the .50mm if the crank journals have been turned.

[Mouglie]

is it possible to replace bearings from under the car if the oil pan is of or should i take the head off?

[boisking]

is it possible to replace bearings from under the car if the oil pan is of or should i take the head off?

Taking the head off will not make it any easier to get to the main bearings (it will actually create a lot more work for you). Getting the oil pan off is the only way to get this done. It will require lifting the engine part-way out of the car, so pulling it completely is not unreasonable.

[channelmaniac]

Take it out and turn it upside down on a motor stand to do it.

MUCH easier. Less likely to damage a bearing since you don't have to hold the crank up while trying to fasten bearing caps in place...